GHK is an endogenous copper peptide that occurs in the tripeptide glycyl-L-histidyl-L-lysine. It has two variants — GHK with or without Cu (Copper). GHK appears to have a strong affinity for copper (II), and it is synthesized from plasma, although it has been isolated in other areas. Endogenous GHK production is considered to decline over time. ^[1]

In cases of injury, GHK may be released from tissue cells. That may be because GHK is present in various proteins that get broken down via hydrolysis during injury. For example, studies suggest that GHK is present in the “alpha 2(I) chain of type I collagen”, which “suggests that the tripeptide might be liberated by proteases at the site of a wound and exert in situ healing.” ^[2] GHK peptide may also be released from the breakdown of another extracellular matrix-binding protein involved in regulating cell shape and proliferation, called SPARC (Secreted Protein, Acidic, and Rich in Cysteine). GHK is found in tissues undergoing remodeling, such as during the process of angiogenesis.^[3]

When GHK is released from the breakdown of proteins like collagen and SPARC, this signaling appears to trigger the fibroblasts to begin synthesizing new collagen and other structural proteins in the skin structure and connective tissues like elastin and glycosaminoglycan. Further, this copper-binding peptide appears to affect genes that control recuperative responses to injury and stress. Its functions appear to include the following: tissue remodeling, anti-inflammatory response, pain perception inhibition, nootropic, anti-cancer action, blood vessel growth, and nerve outgrowth.

Follistatin-344 is a synthetic, full-sized version of a naturally occurring protein bearing the same name. Follistatin-344 occurs in two isomers, varying based on their gene splicing. Follistatin may exist endogenously in two distinct variants, referred to as FST 317 and FST 344. The variants are distinguished by their composition: FST 317 comprises 288 amino acids, whereas FST 344 comprises 315 amino acids. The numerical part of their names reflects the number of amino acids in the precursor molecules from which they are synthesized, with the precursor to FST 317 having 317 amino acids and that to FST 344 having 344 amino acids. It appears that FST 344 is the more commonly occurring form across various tissues. On the other hand, the FST 317 variant likely represents a minor fraction, potentially comprising under 5% of the total mRNA transcript related to Follistatin. Thus, Follistatin-344 appears to be the main constituent. Researchers suggest that its primary role may be to counteract the action of the Tumor Growth Factor-beta (TGF-beta) family. The TGF-beta family comprises Myostatin, Activin, and Follicle Stimulating Growth Hormone (FSH). Follistatin-344 appears to stimulate the Insulin/IGF-1 pathway, and the reported immense potential of the peptide has been published in Follistatin-344 research.

ACE-031 is a soluble protein comprising the type IIB activin receptor (ACVR2B) and the immunoglobulin G1-Fc (IgG1-Fc), and has been studied for its potential in binding and inactivating myostatin, a protein that hampers muscle cell growth. It has been examined during the course of various research studies involved in muscle-wasting disorders and neuromuscular conditions such as Duchenne Muscular Dystrophy (DMD), as well as certain cancers such as those of the prostate or colorectal regions and lipid storage and bone metabolism.

Thymosin Alpha-1, also known as TA1 or Tα1, is a naturally occurring peptide fragment that was discovered in 1972 and researched for its potential action within the context of studies relating to cystic fibrosis, infection (e.g., tuberculosis, cytomegalovirus), respiratory disorders, chronic hepatitis, and cancer. It is also referred to as Thymalfasin when synthetically developed. Originally, research on Thymosin Alpha-1 centered around its potential role in immune modulation. It is hypothesized that it might increase levels of Major Histocompatibility Complex (MHC) class I molecules and boost cytokine production, key components of the immune system that may enhance immune responses.^[1][2] There is also a possibility that it might improve the activity of natural killer cells, which target virus-infected cells and tumors. Furthermore, it might enhance the expression of specific markers on T cells that are considered critical for their identification and function in the immune system, indicating a significant role in immune regulation. Thymosin Alpha-1 is also thought to possibly increase the presence of high-affinity interleukin-2 receptors on cell surfaces, potentially leading to the vigorous activation and proliferation of T lymphocytes, elements of immune response. There is speculation that it may affect both T-helper and cytotoxic T-cell populations, deemed essential for eliminating infected cells. Additionally, it might prompt the differentiation of thymocytes—precursor cells in the thymus—and peripheral blood lymphocytes into mature immune cells, increase natural killer cell numbers, and promote cytokine-driven inflammatory responses. Research also explores its potential role in enhancing macrophage efficiency—cells that engulf and digest pathogens—and in regulating the activity of alpha thrombin, a protein involved in blood clotting, highlighting its broad potential on immune function.

Pal-GHK, also known as Palmitoyl Tripeptide-1 and Palmitoyl Oligopeptide, is a synthetic peptide developed to function in protein production to support the skin’s extracellular matrix (ECM), and skin pigmentation. Pal-GHK is a synthetic hybrid peptide with one fatty acid and one peptide. “Pal” represents Palmitoyl—the covalent attachment of fatty acid to the end of the structure. “GHK” represents glycine-histidine-lysine—the peptide’s amino acid structure. This sequence is thought to be a small fraction of the large protein collagen, which is one of the main proteins in the extracellular matrix of skin and other tissues. The GHK sequence appears to be present in the “alpha 2(I) chain of type I collagen”, and researchers suggest that such a “tripeptide might be liberated by proteases at the site of a wound” as a signal of injury and thus, may be a powerful stimulant for repair.^[1] Particularly, it may signal and attract fibroblasts—cells responsible for synthesizing collagen, elastin, and other proteins in the skin’s extracellular matrix, bones, and connective tissues. “Pal” represents Palmitoyl—the covalent attachment of fatty acid to the end of the structure. The addition of palmitoyl to the molecule is thought to result in better penetration through skin cells and, more specifically, stratum corneum.

TB-500, or synthetic Thymosin Beta-4, also known as synthetic Tβ4, is a synthetic analog of the endogenous Thymosin Beta-4 protein, which is considered to be ubiquitously present in cells. The peptide belongs to a widespread family of 16 related molecules observed to exhibit a high degree of sequence conservation and localization in most tissues and circulating cells. TB-500 was developed to sequester and block actin polymerization in eukaryotic cells.

MOTS-c (mitochondrial open-reading-frame of the 12S rRNA-c) is a 16 amino acid peptide classified as a Mitochondrial-Derived Peptide (MDP), aka “mitochondrial hormone” or “mitokine.” Recent research indicates that MOTS-c is a bioactive peptide closely associated with mitochondrial communication and energy regulation. Initially, researchers hypothesized that it might be most active in the mitochondria, however recent studies suggest otherwise, that MOTS-c may operate via the bloodstream, exhibiting a potentially systemic action.

It is important to note that MOTS-c is a newly identified MDP. Its primary roles are under investigation, but studies include MOTS-c peptide’s influence in cell function and longevity, muscle contractile force, metabolic function and weight regulation.